The Ordnance QF 25 pounder, or more simply, 25-pounder or 25-pdr, was introduced into service just before World War II, during which it served as the major Britishfield gun/howitzer. It was considered by many to be the best field artillery piece of the war, combining high rates of fire with a reasonably lethal shell in a highly mobile piece. It was the British Army's primary artillery field piece well into the 1960s, with smaller numbers serving in training units until the 1980s. Many Commonwealth of Nations countries used theirs in active or reserve service until about the 1970s and ammunition for the weapon is currently being produced by Pakistan Ordnance Factories.

Contents

Design

The design was the result of extended studies looking to replace both the 18 pounder (3.3 inch / 84 mm bore) field gun and the 4.5-inch howitzer (114.3 mm bore), which had been the main field artillery equipments during the First World War. The basic idea was to build a single weapon with the direct-fire capability of the 18 pounder and the high-angle fire of the howitzer, firing a shell about half way between the two in size, around 3.5 to 4 in (90 to 100 mm) of about 30 pounds (14 kg).

Development during the inter-war period was severely hampered by a lack of money, and it was eventually decided to build a "new" design from existing 18 pounders by converting barrels, but designing a new barrel and carriage for production when funds were available. The result was a 3.45 in (87.6 mm) weapon firing a 25 pound (11 kg) HE shell. It was mounted on late model 18 pounder carriages. One of these used a firing platform and this configuration was adopted for the new build guns. The firing platform was lowered and the gun pulled onto it, providing a flat surface that allowed the gunners to quickly turn the weapon in any direction.

Unlike the 18 pounder, the 25 pounder used howitzer type variable charge ammunition. For the Mk 1 Ordnance on 18 pounder carriage this was limited to three different "charges", Charge 1, 2 and 3 in a single cartridge. The 'proper' 25-pdr, Mk 2 Ordnance on Mk 1 Carriage, also had charge super in a separate cartridge. An increment for charge super was introduced in 1942 to provide higher velocity for anti-tank shot. Subsequently these increments were added to charges 2 and 3 to give an additional three charge combinations for use with upper register (high angle) fire. The introduction of the increment to charge super necessitated the addition of the muzzle-brake. 25-pdr was separate loading, the shell was loaded and rammed then the cartridge in its brass case was loaded and the breech closed. In British terminology the 25 pounder was called "Quick Firing" (QF) because the cartridge case provided obturation (it provided the gas seal in the breech) and was automatically released when the breech was opened.

In common with all British guns of the period the indirect fire sight was 'calibrating'. This meant that the range, not elevation angle, was set on the sight. The sight compensated for the difference in the gun's muzzle velocities from standard. The gun was also fitted with a direct fire telescope for use with armour piercing shot. It also used 'one-man laying' in accordance with normal British practice.

An important part of the gun was the ammunition limber ("Trailer, Artillery, No 27"). The gun was hitched to it and the trailer hitched to the tractor when on tow. However, the gun did not need a limber[3] and could be hooked directly to a tractor. The trailer carried ammunition; thirty-two rounds in trays (two rounds per tray) in the trailer protected by two doors. Ammunition was also carried in the gun tractor along with the detachment and various gun stores. Some stores, such as sights, were carried cased on the gun. Each section (two guns) had a third tractor that carried ammunition and towed two ammunition trailers.

The gun detachment comprised the following: No 1 - detachment commander (a sergeant), No 2 - operated the breech and rammed the shell, No 3 - layer, No 4 - loader, No 5 - ammunition, No 6 - ammunition, normally the 'coverer' - second in command and responsible for ammunition preparation and operating the fuze indicator.

The official 'reduced detachment' was 4 men.

Ammunition

"Normal" cartridge arrangements

Display of 25 pdr shells and cases. Left to right: Smoke, Armour-piercing (Pre-1955 UK markings), HE (RDX/TNT, Strange markings), HE (Amatol, Pre-1955 UK markings), Smoke (Pre-1955 UK markings). Although some shells are shown in the cases, the shell and the case were separate items.

The 25 pounder fired separate ammunition; the projectile and the propelling charge in its usually brass cartridge case with its integral primer were loaded separately. Being a QF gun the cartridge case provided obturation.

There were two types of cartridge. The 'Normal' contained three cloth charge bags (coloured red, white and blue) white and/or blue bags would be removed from the cartridge to give "Charge 1" or "Charge 2", all three bags gave "Charge 3". The cartridge case was closed at the top with a leatherboard cup. The second type of cartridge was "Super" it provided charge "Super" only and the bag protruded beyond the top of the cartridge case. In the middle of World War 2 an additional increment bag was introduced to raise the muzzle velocity when firing AP shot with charge Super, this required that a muzzlebrake was fitted[4]. Adoption of "upper register" (high angle) fire needed more charges to improve the range overlap so when necessary increment bags were added to charges 2 and 3 to give a total of 7 charges instead of 4[5].

There were many marks of cartridge mostly differentiated by propellant type. Double base propellant (nitrocellulose/nitroglycerine) was the UK standard but one mark used US single base (nitrocellulose only). However, triple base nitrocellulose/nitroglycerine/picrite) was used throughout the war and eventually replaced all others.[6]

The 25 pounder's main ammunition was the High Explosive (HE) streamlined shell with a 5/10 CRH ogive and boat tail. It was also provided with base ejection smoke (white and coloured), star shells, and chemical shells. Incendiary and coloured flare shells were developed but not introduced into service, and smoke shells were sometimes reloaded with propaganda leaflets or metal foil "window". The UK did not develop a WP smoke shell for the 25 pounder.

For anti-tank use, the 25 pdr was also supplied with a limited amount of 20 pound (9 kg) solid armour-piercing (AP) shot, later replaced with a more potent version with a ballistic cap (APBC). The AP shot was fired with maximum charge, Charge No. 3, Super, or Super with Super Increment depending on the ordnance mark, as muzzle velocity was critical in direct fire for penetration and a flat trajectory.

A shaped charge anti-tank shell was under development in Canada, but the introduction of the QF 17 Pounder, a dedicated anti-tank gun, in 1944 ended its development. After the Second World War, the UK replaced AP shot with a HESH shell. Coloured marked shells (die and PETN) were also developed but not introduced.

The standard fuze is No 117 Direct Action (DA). No 119 (DA and graze) was also used. Combustion or mechanical time fuzes were used with base ejection shells, and mechanical time with graze were used with HE. VT fuzes were used from the end of 1944 and subsequently replaced by CVT fuzes.

British Service

The 25 pounder was the main field artillery gun used by British Commonwealth and colonial infantry and armoured divisions of all types during the Second World War. Throughout the war each British-pattern infantry division was established with seventy two 25 pounders. After mid 1940 each of the division's three field Regiments being issued with 24 guns organised into three 8 gun batteries, before mid 1940 each regiment had two batteries of 12 guns. Armoured divisions had two regiments, from 1944 one of these was equipped with the self-propelled 25-pdr nicknamed Sexton. In the late 1950's UK reverted to batteries of 6 guns, field regiments had 2 batteries on 25 pounder and one of 5.5 inch.

Normally the gun was towed, with its limber, usually behind a Morris C8 4x4 Field Artillery Tractor called a "Quad". The early 18/25 pdrs had been towed in the field by the Dragon Medium Mark IV a tracked vehicle derived from a light tank. After seeing the utility of the M7 Priest, the British introduced the similar Canadian-designed and -built Sexton, mounting the 25 pdr on a Ram tank chassis (itself based on the M3 Lee). Before Sexton the Bishop had been introduced using the Valentine tank chassis. In the 1950s UK replaced the various "Quads" with a new Bedford 3-ton gun tower fitted with a special to purpose body.

Even by WWII standards, the 25 pdr was at the smaller-end of the scale although it had longer range than most other field equipments. However, it was designed to support the proven British doctrine of suppressive (neutralising) fire, not the concept of destructive fire that had proved illusory in the early years of World War I. Most forces had entered the war with even smaller 75 mm designs, but had quickly moved to 105 mm and larger weapons. Nevertheless the 25 pdr was considered by all to be one of the best artillery pieces in use. The devastation caused by the gun (and the speed at which the British artillery control system could respond) in Normandy and the rest of North-West Europe made many German soldiers believe that the British had secretly deployed an automatic 25 pounder. The introduction of NATO standardization led to the replacement of the gun with the 105 mm. The last British military unit to fire the gun in its field role (as opposed to in a ceremonial role) was the Gun Troop of the Honourable Artillery Company on Salisbury Plain in 1992.

A 25 pounder firing a blank

Service With Other Nations

In addition to Commonwealth and colonial forces other Second World War users included the free forces of France, Greece, Poland, Czechoslovakia, Netherlands, Belgium and Luxembourg. The first shot fired by US artillery against the German army in WW2 was fired by a 25Pdr of the 34th Infantry division[7].

After the Second World War 25 pounder remained in service with many Commonwealth armies into the 1960s. It was used in Korea by British, Canadian and New Zealand regiments, and in Malaya by British and Australian batteries. It also featured in wars on the Indian sub-continent and in the service of Israeli and other Middle Eastern armies.

The 25-pounder was extensively used by the Sri Lankan Army during the early years of the Sri Lankan civil war. It still remains in service, although only in a ceremonial role.

In 1949, 48 ex-British Army Mark III 25-pounders were acquired by the Irish Defence Forces, and was in service with the Army Reserve until 2009, having been replaced in the Regular Irish Army by the 105 mm Light Gun in 1981. The Irish Army continues to maintain a 6 gun ceremonial 25 pounder battery for use in state occasions.

Variants

Mark I

Known officially as the Ordnance, Quick Firing 25 pounder Mark I on Carriage 18-pr Mark IV, or Ordnance, Quick Firing 25 pounder Mark I on Carriage 18-pr Mark V and commonly called the 18/25-pr. The Mark IV carriage was a box trail, Mark V was a split trail. These conversions of the 18 pdr first entered British service in the late 1930s. A few were lost in the Norwegian campaign and 704 in France, leaving about the same number in UK's global stocks. They served in North Africa (until about late 1941) and Malaya. This mark of 25 pdr was limited to charge 3 due to its 18 pdr carriage.

Mark II

The Mark II, fitted to the Mark 1 carriage was the standard gun during World War 2. They were built in Australia and Canada but mostly in UK. Deliveries (from UK production) started at the beginning of 1940 and first entered service with a Canadian regiment stationed in UK during May 1940. No Ordnance 25-pr Mk 2 on Carriage 25-pr Mark 1 were lost in France. This gun fired all charges, 1 - 3 and Super. A later addition were charge increments. These were added to Charge Super for direct fire anti-tank and necessitated the adoption of a muzzle brake to reduce recoil. Guns with this modification were known as the Mark 2/1. The distinctive brake is a well-known feature of the gun that makes it easily recognized.

Mark III

The Mark III ordnance was a Mk. II with a modified receiver to prevent the rounds from slipping back out when loading at high angles. With the muzzle brake they became the Mark III/1, while the Mark IV were identical new-build versions which all featured the brake.

In Burma a local modification produced a narrower wheelbase (by about 20-inches) called the Jury Axle. This was suitable for towing by Jeep and could be loaded into a Dakota aircraft. It was subsequently adopted officially with other minor modifications and a new platform for the narrow wheelbase as the Carriage 25 pdr Mark 2. The Mark 3 Carriage, also narrow, included a hinge to make it easier to fire the gun in the upper register (high angle). High angle fire had been introduced in Italy and used the increments originally introduced for anti-tank fire, adding them to charges 2 and 3 to give 25-pdr 7 charges.

Short, Mark I

The 25 pounder Short Mark I, or Baby 25 pr, was an Australianpack gun version of the 25 pounder, first produced in 1943. This was a shortened version of the standard 25 pounder, mounted on the Carriage 25 pr Light, Mark 1. The Baby was intended for jungle warfare and was only used by Australian units in the South West Pacific theatre of World War II. The gun could be towed by a jeep or broken down into 13 sections and transported by air. During the New Guinea campaign the gun was manhandled up steep jungle tracks where trucks could not operate.

Bishop

The Bishop was a British self-propelled 25-pounder utilising the Valentine tank chassis.

Sexton

The Sexton was a Canadian self-propelled 25-pounder utilising the Ram or Grizzly tank chassis.

Yeramba

The Yeramba was an Australian self-propelled 25-pounder utilising the M3 Lee tank chassis.